Grassman M
Department of Biology, Memphis State University, TN 38152.
Brain Behav Evol. 1993;41(3-5):224-8. doi: 10.1159/000113842.
It has been widely believed for several decades that hatchling sea turtles imprint to chemical cues characteristic of their natal beach and use this information as part of a repertoire of mechanisms enabling their return to the same beach for mating and nesting. This has proven very difficult to test. Although the imprinting theory is conceptually simple, functionally it is quite complex. This involves not only chemical imprinting of nestlings but growth and migration to habitats where the adults are found, long-term memory of their earlier chemical exposure, reproductive maturation, and homing. A few studies have been conducted to examine these elements of the imprinting theory. Experiments involving the exposure of embryos and hatchlings to chemicals suggest that juvenile turtles 'imprint' to the chemical environment of their nest. This can be termed chemical imprinting. Loggerhead turtles, Caretta caretta, and ridley turtles, Lepidochelys kempi, appear to be attracted to chemicals (morpholine and natural seawater, respectively) to which they were exposed as embryos. The strongest support for chemical imprinting is that six-month-old green turtles, Chelonia mydas, exposed to either morpholine or 2-phenylethanol in the nest and for a period of time after hatching, respond similarly to the chemical to which they were exposed as nestlings. Although chemical imprinting does not 'prove' the imprinting theory of turtle homing, it is a necessary component of the theory not previously examined.
几十年来，人们普遍认为，刚孵化出的海龟会对其出生地海滩特有的化学线索产生印记，并将这些信息作为其一系列机制的一部分，使其能够回到同一海滩进行交配和筑巢。事实证明，这很难进行测试。虽然印记理论在概念上很简单，但在功能上却相当复杂。这不仅涉及雏龟的化学印记，还包括生长以及向发现成年海龟的栖息地的迁移、对它们早期接触过的化学物质的长期记忆、生殖成熟和归巢。已经进行了一些研究来检验印记理论的这些要素。涉及将胚胎和幼龟暴露于化学物质的实验表明，幼年海龟会对其巢穴的化学环境产生“印记”。这可以称为化学印记。蠵龟（Caretta caretta）和丽龟（Lepidochelys kempi）似乎会被它们在胚胎期接触过的化学物质（分别是吗啉和天然海水）所吸引。对化学印记最有力的支持是，在巢穴中以及孵化后的一段时间内接触过吗啉或2-苯乙醇的6个月大绿海龟（Chelonia mydas），对它们在雏龟期接触过的化学物质有类似的反应。虽然化学印记并不能“证明”海龟归巢的印记理论，但它是该理论中一个以前未被研究过的必要组成部分。
